U.S. Pat. No. 6,409,001 (Kerr), hereby incorporated by reference in its entirety as if set forth fully herein, discloses a multi-directional coupling including a tubular slipper, a tubular member, a race, and roller members disposed in channels defined by the tubular slipper and the tubular member. Torque applied to the member forces the rollers to roll up the side walls of the channel pockets (or recesses), forcing the slipper to radially expand, thereby increasing the radial force exerted on the slipper against the race. As more torque is applied to the member, the slipper and the race become rotationally locked to the member.
Kerr is limited in that the tubular slipper and tubular member each include a pocket for every roller. Pockets are typically produced by complex forming or machining, both of which are expensive processes. Thus, there is a long-felt need for a multi-directional coupling with fewer pockets and staggered roller elements.